All Set for Carlsbad Dredging Project

Carlsbad beaches will soon have more sand as a result of the Agua Hedionda Lagoon dredging project – starting this February until mid April, informs the City of Carlsbad, California. The lagoon has been dredged every one to four years since 1954 as part of the Encina power plant operations. The last time the lagoon was dredged was three years ago, in 2018. Now that the Encina plant has been retired, Poseidon Water is taking over the dredging, as part of an agreement when the seawater desalination plant was built and came online in 2015.

San Diego regional water quality regulators issued a new permit for the development of permanent, stand-alone seawater intake and discharge facilities at the Carlsbad Desalination Plant. Photo: Water Authority

New Permit Fosters Sustainable Water Production at Carlsbad Desalination Plant

San Diego regional water quality regulators today issued a permit for the installation of new, technologically advanced and environmentally sensitive seawater intake and discharge facilities at the Claude “Bud” Lewis Carlsbad Desalination Plant.

The plant – and the new permit – support Gov. Gavin Newsom’s April 29 executive order for California “to think differently and act boldly by developing a comprehensive strategy to build a climate-resilient water system.”

Under the new National Pollution Discharge Elimination System (NPDES) permit, the Carlsbad plant will continue producing about 50 million gallons a day of high-quality, drought-proof drinking water for the region as Poseidon Water and the San Diego County Water Authority develop a permanent, stand-alone seawater intake and associated structures.

Environmentally sensitive facility

The new intake-discharge system is needed for long-term operations of the nation’s largest seawater desalination plant, which started commercial production in December 2015 using water withdrawn from Agua Hedionda Lagoon for once-through cooling at the Encina Power Station. So far, it has produced more than 46 billion gallons of drinking water with reverse osmosis technology.

“The Carlsbad Desalination Plant is an invaluable asset for the state and region that helps us adapt to the changing climate and sustain a $231 billion regional economy,” said Jim Madaffer, chair of the Water Authority’s Board of Directors. “It is the most environmentally sensitive and technologically advanced plant of its kind in the nation – part of our commitment to collaborative projects and integrated water solutions for San Diego and the Southwest.”

Water supply sustainability

The closure of the power station in December 2018 led to temporary intake-discharge operations that will continue while new, stand-alone desal intake-discharge facilities are built. Conversion to stand-alone operations was anticipated in the 2012 Water Purchase Agreement between Poseidon, which owns and operates the desalination plant, and the Water Authority, which purchases the water for regional use. Currently, the plant provides about 10 percent of the region’s water supply.

“We are very thankful to the Regional Board for supporting the environmental enhancements of the Carlsbad project and water supply reliability for San Diego County,” said Poseidon CEO Carlos Riva. “This plant will continue to be a vital regional resource for decades to come and an example of how environmental stewardship can go hand-in-hand with water supply sustainability.”

Peter MacLaggan, senior vice president of project development with Poseidon Water, describes the water quality improvement at the Carlsbad Desalination Plant during a regional water quality control board public hearing in San Diego on May 8, 2019.

Transition in three phases

With the permit in hand, the transition to the new intake and discharge facilities will be implemented in three phases:

  • Temporary Operations – NRG, which owns Encina Power Station, continues to operate the water circulation pumps while an interim intake system is constructed.
  • Interim Operations – Expected to begin in mid-2020, this phase uses new fish-friendly pumps as a replacement for the existing circulation pumps. A new, permanent screened intake system also will be designed and built in the lagoon during this phase of operation. The new intake will rely on innovative technology, including 1 mm screens that will further enhance marine life protection.
  • Permanent Operations – The new submerged, screened-intake system is expected to be connected in late 2023, achieving the best available technology to minimize impacts to marine life in full compliance with the 2015 California Ocean Plan Amendment.

Once permanent operations begin, the Carlsbad Desalination Plant will be the first to comply with the 2015 Ocean Plan Amendment, designed to advance ocean water as a reliable supplement to traditional water supplies while protecting marine life and water quality.

Environmental stewardship

Poseidon is also protecting the coastal environment by taking over responsibility for the preservation of Agua Hedionda Lagoon from NRG. As the lagoon’s steward, Poseidon Water is taking responsibility for ensuring the man-made lagoon continues to realize the life-sustaining benefits of an open connection to the Pacific Ocean through periodic maintenance dredging.

Dredging keeps sand from blocking the flow of ocean water in and out of the lagoon, maintaining its tidal circulation, which is needed to maintain a healthy marine ecosystem, support extensive recreational uses, sustainable aquaculture at Carlsbad Aquafarm, and a white seabass hatchery operated by Hubbs-SeaWorld. Dredging also helps replenish the sand on Carlsbad State Beach, which otherwise would revert to historical cobble-stone, with sand that is relocated from the lagoon to nearby shoreline.

Temporary operations are anticipated to cost about $6.5 million annually, increasing the cost of water from the plant in 2020 by about $135 per acre-foot. Permanent facilities are projected to cost between $66 million and $83 million. The Water Authority is seeking state grant funds to defray some of that cost.

The Water Authority purchases up to 56,000 acre-feet of water from the Carlsbad plant per year – enough to serve approximately 400,000 people annually. The plant is a major component of the Water Authority’s multi-decade strategy to diversify the county’s water supply portfolio and minimize vulnerability to drought or other water supply emergencies.

Poseidon Water has assumed the stewardship of the Agua Hedionda Lagoon and will help preserve over 400 acres of coastal habitat. Photo: Poseidon Water

Poseidon Water Assumes Stewardship of Agua Hedionda Lagoon

Poseidon Water, a national leader in the development of water supply and treatment projects using a public-private partnership approach, furthered its commitment to protect and preserve San Diego’s coastal environment by assuming stewardship of the Agua Hedionda Lagoon in Carlsbad.

The Agua Hedionda Lagoon encompasses over 400 acres of marine, estuarine and wetlands habitat teeming with hundreds of fish, invertebrate and bird species. The lagoon has long been home to youth recreation activities, including the YMCA Aquatic Park (affectionately known to its patrons as “Camp H2O”), as well as popular activities for visitors of all ages, such as kayaking, swimming, canoeing and paddle-boarding. As the lagoon’s steward, Poseidon Water is taking responsibility for ensuring the man-made lagoon continues to realize the life-sustaining benefits of an open connection to the Pacific Ocean.

Maintaining healthy marine ecosystem

Poseidon Water is ensuring the ongoing vitality of this magnificent estuary through periodic maintenance dredging. Dredging keeps sand from blocking the flow of ocean water in and out of the lagoon, maintaining its tidal circulation, which is needed to maintain a healthy marine ecosystem, support extensive recreational uses, sustainable aquaculture (Carlsbad Aquafarm) and a white seabass fish hatchery (Hubbs-SeaWorld Fish Hatchery). Dredging also helps replenish the sand on Carlsbad State Beach, which otherwise would revert to historical cobble-stone, with sand that is relocated from the lagoon to nearby shoreline, ensuring the local beaches are attractive for local residents and visitors to enjoy.

“The Agua Hedionda Lagoon Foundation has been dedicated to providing direct access to nature while ensuring the environmental protection of the lagoon,” said Lisa Cannon-Rodman, chief executive officer of the Agua Hedionda Lagoon Foundation. “We are thrilled that Poseidon Water will continue in these efforts and can confidently say that the community will continue to experience the splendor of this unique environment for many years to come.”

Unique lagoon environment

Some of the uses that make up this unique environment include:

1. Man-Made Marine Estuary – Aqua Hedionda Lagoon is a man-made estuary consisting of 400 acres of inter-tidal wetlands and uplands that are home to a wide variety of fish, invertebrates, animals and birds.
2. Claude “Bud” Lewis Carlsbad Desalination Plant – The Carlsbad Desalination Plant produces over 50 million gallons of high-quality and climate-resilient drinking water each day, serving approximately 10 percent of the region’s water demand.
3. YMCA Aquatic Park – The YMCA Aquatic Park, better known as Camp H2O, is a summer camp geared towards children ages seven to twelve that offers affordable day camp activities including swimming, kayaking, boating and fishing. The camp plays an important role in educating youth about the precious marine environment and the need to preserve the lagoon for future generations.
4. Hubbs-SeaWorld Fish Hatchery – Hubbs-SeaWorld Resources Enhancement and Hatchery Program include a 22,000 square-foot fish hatchery on the lagoon. The Program actively contributes to the restoration of the California white seabass population, adding over 350,000 juveniles annually. Hubbs-SeaWorld has begun to expand its marine restoration activities as a result of additional acreage donated by the Desalination Plant.
5. Recreational Boating – Boating remains one of the most popular lagoon activities for residents and visitors alike. California Water Sports offers expert lessons and rents a variety of boats, including kayaks, canoes and paddleboards to the public.
6. Carlsbad Aquafarm – The lagoon is home to the Carlsbad Aquafarm, Southern California’s only shellfish aquafarm, where over 1.5 million pounds of shellfish are sustainably harvested each year. The farm is a growing contributor to the $1.5 billion U.S. aquafarming industry and the San Diego region’s local economy.
7. Agua Hedionda Lagoon Foundation Discovery Center – Opened in 2006, the Discovery Center offers visitors an opportunity to learn about the lagoon’s native plants and marine life through exhibits and educational programs and hosts more than 8,700 local students each year.

Lagoon preservation

“Agua Hedionda Lagoon plays a key role not just in our environment, but also Carlsbad’s quality of life and economy,” said City of Carlsbad Mayor Matt Hall. “By ensuring the lagoon’s long-term preservation, Poseidon Water has once again demonstrated its commitment to Carlsbad and environmental sustainability.”

The Lagoon was previously maintained by NRG, owner of the now decommissioned Encina Power Station. The Carlsbad Desalination Plant is located on the same site as the Encina Power Station and utilizes the power plant’s historic intake and outfall facilities for the desalination process. As part of its co-location, Poseidon Water has long planned to succeed NRG as the lagoon’s steward.

With the decommissioning of Encina Power Station, the Carlsbad Desalination Plant is modernizing the existing intake facilities to provide include additional environmental enhancements to protect and preserve the marine environment.

“Our location along the shore of the Agua Hedionda Lagoon makes it a critical part of the Carlsbad Desalination Plant’s operations, which enables us to provide San Diego County with more than 50 million gallons of high-quality drinking water every day,” said Carlos Riva, Poseidon Water CEO. “We look forward to taking an even more active role in the protection and preservation of the lagoon so that we can all enjoy its recreational and marine resources now and for generations to come.”

Assuming responsibility for the lagoon is just the latest in Poseidon Water’s long history of environmental stewardship in California, by employing 100 percent carbon neutral desalination technology at its Carlsbad Desalination Plant – making it the first major infrastructure project in California to eliminate its carbon footprint – and committing to do the same at its proposed Huntington Beach Seawater Desalination Plant. These efforts continue to assist communities in becoming water independent and less susceptible to dangerous drought conditions, without any carbon emissions.